Question

Which answer is the explicit rule for the sequence: 13, 10.5, 8, 5.5, 3, 0.5, ...

Answer 1

`a_n`
`= 15.5-2.5n`

Explanation:

Answer 2

Answer: The explicit rule for the sequence will be

`a_n=15.5-2.5n`

Explanation:

Since we have given that

`13,10.5,8,5.5,3,0.5.....`

Here,

a = first term = 13

d = common difference

`a_2-a_1 = 10.5-13=-2.5`

Since it forms an A.P. ;

`a_n=a+(n-1)d\\\\a_n=13+(n-1)(-2.5)\\\\a_n=13-2.5n+2.5\\\\a_n=15.5-2.5n`

Hence, the explicit rule for the sequence will be

`a_n=15.5-2.5n`